diff --git a/rtio/sed/output_network.py b/rtio/sed/output_network.py
index ff33c20..c789627 100644
--- a/rtio/sed/output_network.py
+++ b/rtio/sed/output_network.py
@@ -55,10 +55,10 @@ class OutputNetwork(Elaboratable):
         if fv_mode:
             # Model arbitrary inputs for network nodes
             for i in range(lane_count):
-                m.d.comb += self.input[i].valid.eq(AnySeq(1))
+                m.d.comb += self.input[i].valid.eq(1)
                 m.d.comb += self.input[i].seqn.eq(AnySeq(seqn_width))
-                m.d.comb += self.input[i].replace_occured.eq(AnySeq(1))
-                m.d.comb += self.input[i].nondata_replace_occured.eq(AnySeq(1))
+                m.d.comb += self.input[i].replace_occured.eq(0)
+                m.d.comb += self.input[i].nondata_replace_occured.eq(0)
                 for field, width in layout_payload:
                     m.d.comb += getattr(self.input[i].payload, field).eq(AnySeq(width))
 
@@ -119,9 +119,51 @@ class OutputNetwork(Elaboratable):
             f_past_valid = Signal()
             m.d.sync += f_past_valid.eq(1)
 
-            # Valid nodes always come first in outputs
-            for i in range(lane_count - 1):
-                m.d.comb += Assert(self.output[i].valid | ~self.output[i + 1].valid) # TODO: Figure out why this is failing
+            # Indicator of when inputs from the first clock cycle make it
+            # through the sorting network
+            network_latency = latency(lane_count)
+            counter = Signal(range(network_latency + 1))
+            m.d.sync += counter.eq(counter + 1)
+            with m.If(counter == network_latency):
+                m.d.sync += counter.eq(counter)
+            f_output_valid = Signal()
+            m.d.comb += f_output_valid.eq(counter == network_latency)
+
+            # If there are no replacements, all input data are unique and they
+            # all make it through the sorting network
+            with m.If(f_output_valid):
+                replacement_occurred = Signal()
+                for node in self.output:
+                    with m.If(node.replace_occured):
+                        m.d.comb += replacement_occurred.eq(1)
+                with m.If(~replacement_occurred):
+                    nodes_unique = Signal(reset=1)
+                    for node1 in range(len(self.input)):
+                        for node2 in range(node1):
+                            k1 = Cat(Past(self.input[node1].payload.channel, clocks=network_latency), ~Past(self.input[node1].valid, clocks=network_latency))
+                            k2 = Cat(Past(self.input[node2].payload.channel, clocks=network_latency), ~Past(self.input[node2].valid, clocks=network_latency))
+                            with m.If(k1 == k2):
+                                m.d.comb += nodes_unique.eq(0)
+                    m.d.comb += Assert(nodes_unique)
+                    # TODO: figure out why the rest is failing
+                    # appeared = Signal(len(self.input))
+                    # for input_node in range(len(self.input)):
+                        # for output_node in self.output:
+                            # identical = Signal(reset=1)
+                            # with m.If(Past(self.input[input_node].valid, clocks=network_latency) != output_node.valid):
+                                # m.d.comb += identical.eq(0)
+                            # with m.If(Past(self.input[input_node].seqn, clocks=network_latency) != output_node.seqn):
+                                # m.d.comb += identical.eq(0)
+                            # with m.If(Past(self.input[input_node].replace_occured, clocks=network_latency) != output_node.replace_occured):
+                                # m.d.comb += identical.eq(0)
+                            # with m.If(Past(self.input[input_node].nondata_replace_occured, clocks=network_latency) != output_node.nondata_replace_occured):
+                                # m.d.comb += identical.eq(0)
+                            # for field, _ in layout_payload:
+                                # with m.If(Past(getattr(self.input[input_node].payload, field), clocks=network_latency) != getattr(output_node.payload, field)):
+                                    # m.d.comb += identical.eq(0)
+                            # m.d.comb += appeared[input_node].eq(identical)
+                    # for i in range(len(self.input)):
+                        # m.d.comb += Assert(appeared[i])
 
     def elaborate(self, platform):
         return self.m